in reply to Reading file and matching lines

In the name of Tim Toady (There Is More Than One Way To Do It). Featuring the range, or flip-flop operator, which translates in human as "From .. till ..", and the next keyword.

my $count =0;
LINE: while(<DATA>)
{
   next LINE unless /^E/../^G/; # next line unless we are between a li
+ne starting with a end a line starting with G
   die "Oups, went too far!" if /^h/; # error if the line starts with 
+an h and hasn't been skipped by the previous statment
   $count++ unless /^G/; # count that do not start with a G
}

__DATA__
Q165HWN0X001
Q165HWN0X002
Q165HWN0X003
E99HEADER|006|001
E99INSSCH|052|
E99POLCOM|1||IIL|62|35119849249024|||||
E99INSFAC2|C00124||||||XAJX0727,YGAX0000,ZAAJ0203,VABA0018,WJZA1800|
G35119849249024
h189SMA2

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Re^2: Reading file and matching lines
by tbone654 (Beadle) on Feb 11, 2014 at 20:26 UTC

    One liner

    Prompt> perl -ne ' next if !/^E/; print $_; ' datafile

E99HEADER|006|001
E99INSSCH|052|
E99POLCOM|1||IIL|62|35119849249024|||||
E99INSFAC2|C00124||||||XAJX0727,YGAX0000,ZAAJ0203,VABA0018,WJZA1800|
[reply]

      modified one-liner and data to test... 

      F98020A@LUS76E8012758 /cygdrive/c/package
$ perl -ne ' if (/^h/){print "error starts with h program exiting"; exit;} if (/^G/){exit;} next if !/^E/; print $_;' data
E99HEADER|006|001
E99INSSCH|052|
E99POLCOM|1||IIL|62|35119849249024|||||
E99INSFAC2|C00124||||||XAJX0727,YGAX0000,ZAAJ0203,VABA0018,WJZA1800|

F98020A@LUS76E8012758 /cygdrive/c/package
$ cat data  (note: changed the data to have E's after old)
Q165HWN0X001
Q165HWN0X002
Q165HWN0X003
E99HEADER|006|001
E99INSSCH|052|
E99POLCOM|1||IIL|62|35119849249024|||||
E99INSFAC2|C00124||||||XAJX0727,YGAX0000,ZAAJ0203,VABA0018,WJZA1800|
G35119849249024
h189SMA2
E99INSSCH|052|
E99POLCOM|1||IIL|62|35119849249024|||||
E99INSFAC2|C00124||||||XAJX0727,YGAX0000,ZAAJ0203,VABA0018,WJZA1800|
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